Lithium Battery Coating for High-Voltage Stability
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Solution Overview
Problem
Rechargeable lithium batteries face performance deterioration and safety issues due to electrolyte solution decomposition and side reactions at high voltages and temperatures, leading to increased internal resistance and reduced cycle life.
Innovation Solution
A rechargeable lithium battery design incorporating a positive electrode with lithium composite oxide and an electrolyte solution containing a non-aqueous organic solvent, lithium salt, and an additive represented by Chemical Formula 1, which forms a solid electrolyte interface film with high-temperature stability and suppresses side reactions, reducing gas generation and internal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the voltage range is expanded to increase energy density, then the energy density is improved, but the positive electrode performance deteriorates due to electrolyte solution oxidization
Solution Approach 1:
A coating layer comprising at least one metal element selected from the group consisting of Li, Na, Mg, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Ag, In, Sn, Sb, Te, I, Pt, and Au is formed on the surface of the positive active material particles. This coating layer acts as an intermediary barrier between the electrolyte solution and the positive electrode, preventing direct contact and chemical reactions. The coating layer suppresses electrolyte oxidization while allowing ionic transport, thus maintaining electrode performance even at expanded voltage ranges and high energy density conditions.
2Productivity
If LiPF6 is used as lithium salt to achieve high capacity, then the charging rate is improved, but gas generation increases and safety deteriorates at high temperature
Solution Approach 1:
The coating layer on the positive electrode surface acts as a protective intermediary that prevents direct contact between LiPF6 and the electrolyte solution at high temperatures. This barrier suppresses the decomposition reactions that generate gas, while still allowing efficient ionic transport to maintain high charging rates. The coating layer stabilizes the interface, preventing the harmful side reactions that would otherwise occur with LiPF6 at elevated temperatures.
3Productivity
If the charging rate is increased to improve productivity, then the charging speed is improved, but the internal resistance increases due to electrolyte decomposition
Solution Approach 1:
A coating layer comprising at least one metal element selected from the group consisting of Li, Na, Mg, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Ag, In, Sn, Sb, Te, I, Pt, and Au is preliminarily formed on the surface of the positive active material particles before battery operation. This pre-formed coating layer prevents electrolyte decomposition during high-rate charging by blocking direct contact between the electrolyte and electrode surface. By establishing this protective barrier in advance, the battery can achieve high charging speeds without the electrolyte decomposition that would otherwise increase internal resistance.
4Use of energy by moving object
If high voltage is applied to increase energy density, then the energy capacity is improved, but the electrolyte solution decomposes and generates decomposition products
Solution Approach 1:
The coating layer on the positive electrode serves as a stable intermediary barrier that prevents direct contact between the high-voltage electrode environment and the electrolyte solution. This coating layer is electrochemically stable at high voltages and prevents the electrolyte decomposition that would otherwise occur under high voltage conditions. The coating allows ionic transport necessary for high energy capacity while blocking the chemical reactions that lead to electrolyte decomposition and gas generation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution improves battery stability, cycle life, and high-temperature storage characteristics by preventing electrolyte decomposition and side reactions, thereby reducing internal resistance and failure rates.
Implementation Method 1
an electrolyte solution containing a non-aqueous organic solvent, a lithium salt, and an additive represented by Chemical Formula 1, which forms a solid electrolyte interface film with high-temperature stability
Data Source
AI summary
A rechargeable lithium battery includes a positive electrode including a positive active material; a negative electrode including a negative active material; and an electrolyte solution including a non-aqueous organic solvent, a lithium salt, and an additive, wherein the additive includes a compound represented by Chemical Formula 1, and the positive active material includes at least one lithium composite oxide represented by Chemical Formula 3.